Supercoils in prokaryotic DNA restrained in vivo.
AUTOR(ES)
Pettijohn, D E
RESUMO
Cells of Escherichia coli containing the plasmid F were gamma-irradiated with various doses to introduce determined numbers of single-strand breaks in the F DNA. The cells were then incubated to permit repair of the breaks while DNA gyrase was inhibited with coumermycin to limit restoration of any relaxed supercoil. Repaired, covalently continuous F DNA was isolated and its superhelical density was measured by two different methods. Both indicated that a major part (50-60%) of the negative superhelical turns were maintained in the repaired molecules, suggesting that the supercoils are restrained in vivo.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=348488Documentos Relacionados
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